import * as core from "@actions/core";
import { agents } from "./agents/index.ts";
import type { PayloadEvent } from "./external.ts";
import { reportProgress } from "./mcp/comment.ts";
import { startInstallation } from "./mcp/dependencies.ts";
import { startMcpHttpServer, type ToolContext } from "./mcp/server.ts";
import { computeModes } from "./modes.ts";
import { initToolState } from "./toolState.ts";
import {
  type ActivityTimeout,
  createProcessOutputActivityTimeout,
  DEFAULT_ACTIVITY_CHECK_INTERVAL_MS,
  DEFAULT_ACTIVITY_TIMEOUT_MS,
} from "./utils/activity.ts";
import { recordDiffReadFromToolUse } from "./utils/diffCoverage.ts";
import { onExitSignal } from "./utils/exitHandler.ts";
import { resolveGit, setGitAuthServer } from "./utils/gitAuth.ts";
import { startGitAuthServer } from "./utils/gitAuthServer.ts";
import { createGiteaClient } from "./utils/gitea.ts";
import { resolveInstructions } from "./utils/instructions.ts";
import { executeLifecycleHook } from "./utils/lifecycle.ts";
import { log } from "./utils/cli.ts";
import { normalizeEnv } from "./utils/normalizeEnv.ts";
import { resolveOutputSchema, resolvePayload, resolvePromptInput } from "./utils/payload.ts";
import { defaultRepoSettings } from "./utils/runContext.ts";
import { setupGit, createTempDirectory, wipeRunnerLeakSurface } from "./utils/setup.ts";
import { killTrackedChildren } from "./utils/subprocess.ts";
import { resolveTimeoutMs, TIMEOUT_DISABLED } from "./utils/time.ts";
import { Timer } from "./utils/timer.ts";
import { createTodoTracker } from "./utils/todoTracking.ts";

export interface MainResult {
  success: boolean;
  output?: string | undefined;
  error?: string | undefined;
  result?: string | undefined;
}

function parseRepoContext(): { owner: string; name: string } {
  const githubRepo = process.env.GITHUB_REPOSITORY;
  if (!githubRepo) {
    throw new Error("GITHUB_REPOSITORY environment variable is required");
  }
  const [owner, name] = githubRepo.split("/");
  if (!owner || !name) {
    throw new Error(`Invalid GITHUB_REPOSITORY format: ${githubRepo}. Expected 'owner/repo'`);
  }
  return { owner, name };
}

/**
 * When the workflow passes a plain-string prompt, infer the event context
 * from Gitea Actions environment variables (GITHUB_EVENT_NAME, GITEA_PR_NUMBER).
 * Returns null when the env vars aren't set (e.g. local dev run).
 */
function resolveEventFromEnv(): PayloadEvent | null {
  const eventName = process.env.GITHUB_EVENT_NAME;
  const prNumberRaw = process.env.GITEA_PR_NUMBER;
  const prNumber = prNumberRaw ? parseInt(prNumberRaw, 10) : NaN;

  if (eventName === "pull_request" && !Number.isNaN(prNumber)) {
    return {
      trigger: "pull_request_opened",
      issue_number: prNumber,
      is_pr: true,
      title: process.env.GITEA_PR_TITLE ?? "",
      body: null,
      branch: process.env.GITHUB_HEAD_REF ?? "",
    };
  }

  if (eventName === "issue_comment" && !Number.isNaN(prNumber)) {
    return {
      trigger: "issue_comment_created",
      issue_number: prNumber,
      is_pr: true,
      comment_id: 0,
      comment_type: "issue",
      body: null,
    };
  }

  return null;
}

export async function main(): Promise<MainResult> {
  normalizeEnv();

  const timer = new Timer();
  let activityTimeout: ActivityTimeout | null = null;
  let safetyNetTimer: NodeJS.Timeout | undefined;

  const resolvedPromptInput = resolvePromptInput();
  const repoSettings = defaultRepoSettings();
  const payload = resolvePayload(resolvedPromptInput, repoSettings);

  // When the prompt is a plain string and the event resolved to "unknown",
  // patch the event from Gitea Actions environment variables so the agent
  // knows which PR to review.
  if (payload.event.trigger === "unknown") {
    const envEvent = resolveEventFromEnv();
    log.info(
      `» event resolution: GITHUB_EVENT_NAME=${process.env.GITHUB_EVENT_NAME ?? "(unset)"}, ` +
        `GITEA_PR_NUMBER=${process.env.GITEA_PR_NUMBER ?? "(unset)"}, ` +
        `resolved=${envEvent ? `${envEvent.trigger} #${(envEvent as { issue_number?: number }).issue_number}` : "null"}`
    );
    if (envEvent) {
      (payload as { event: PayloadEvent }).event = envEvent;
    }
  }

  const toolState = initToolState({
    progressComment: payload.progressComment,
  });

  resolveGit();

  const repoContext = parseRepoContext();
  const gitea = createGiteaClient();

  const tmpdir = createTempDirectory();
  toolState.model = payload.model ?? process.env.OLLAMA_MODEL ?? "qwen3.6:35b";

  if (payload.event.trigger === "pull_request_synchronize") {
    toolState.beforeSha = payload.event.before_sha;
  }

  wipeRunnerLeakSurface();

  const botToken = process.env.BOT_TOKEN;
  if (!botToken) {
    throw new Error("BOT_TOKEN environment variable is required");
  }

  let toolContext: ToolContext | undefined;
  let progressCallbackDisabled = false;
  let todoTracker: ReturnType<typeof createTodoTracker> | undefined;

  try {
    if (payload.cwd && process.cwd() !== payload.cwd) {
      process.chdir(payload.cwd);
    }

    await using gitAuthServer = await startGitAuthServer(tmpdir);
    setGitAuthServer(gitAuthServer);

    await setupGit({
      gitToken: botToken,
      owner: repoContext.owner,
      name: repoContext.name,
      gitea,
      toolState,
      shell: payload.shell,
      postCheckoutScript: repoSettings.postCheckoutScript,
    });
    timer.checkpoint("git");

    const setupHook = await executeLifecycleHook({
      event: "setup",
      script: repoSettings.setupScript,
      normalizeWorkingTreeAfter: true,
    });
    if (setupHook.warning) {
      throw new Error(setupHook.warning);
    }
    timer.checkpoint("lifecycleHooks::setup");

    const agentId = "ollama" as const;
    const modes = computeModes(agentId);
    const outputSchema = resolveOutputSchema();

    let defaultBranch = "main";
    try {
      const repoData = await gitea.request(
        "GET /repos/{owner}/{repo}",
        { owner: repoContext.owner, repo: repoContext.name }
      );
      defaultBranch = (repoData.data as { default_branch?: string }).default_branch ?? "main";
    } catch { /* keep "main" fallback */ }

    toolContext = {
      agentId,
      repo: { ...repoContext, defaultBranch },
      payload,
      gitea,
      gitToken: botToken,
      modes,
      postCheckoutScript: repoSettings.postCheckoutScript,
      prepushScript: repoSettings.prepushScript,
      prApproveEnabled: repoSettings.prApproveEnabled,
      modeInstructions: repoSettings.modeInstructions,
      toolState,
      mcpServerUrl: "",
      tmpdir,
    };

    await using mcpHttpServer = await startMcpHttpServer(toolContext, { outputSchema });
    toolContext.mcpServerUrl = mcpHttpServer.url;
    log.info(`» MCP server started at ${mcpHttpServer.url}`);
    timer.checkpoint("mcpServer");

    startInstallation(toolContext);

    const instructions = resolveInstructions({
      payload,
      repo: { owner: repoContext.owner, name: repoContext.name, defaultBranch },
      modes,
      agentId,
      outputSchema,
    });

    log.info(`» starting shockbot (model: ${toolState.model})`);

    activityTimeout = createProcessOutputActivityTimeout({
      timeoutMs: DEFAULT_ACTIVITY_TIMEOUT_MS,
      checkIntervalMs: DEFAULT_ACTIVITY_CHECK_INTERVAL_MS,
    });
    activityTimeout.promise.catch(() => {});

    todoTracker = createTodoTracker(async (body) => {
      if (progressCallbackDisabled || !toolContext) return;
      try {
        await reportProgress(toolContext, { body });
      } catch (err) {
        log.debug(`progress update failed: ${err}`);
      }
    });
    toolState.todoTracker = todoTracker;

    onExitSignal(() => {
      todoTracker?.cancel();
    });

    let innerTimeoutFired = false;
    const onInnerActivityTimeout = () => {
      if (innerTimeoutFired) return;
      innerTimeoutFired = true;
      log.info("» inner activity timeout fired — stopping MCP server");
      mcpHttpServer[Symbol.asyncDispose]().catch((err) => {
        log.debug(`mcp server stop after inner kill failed: ${err instanceof Error ? err.message : String(err)}`);
      });
      safetyNetTimer = setTimeout(
        () => {
          activityTimeout?.forceReject("agent still pending 5min after inner activity kill — forcing exit");
        },
        5 * 60 * 1000
      );
      safetyNetTimer.unref?.();
    };

    const agentPromise = agents.ollama.run({
      payload,
      model: toolState.model,
      mcpServerUrl: mcpHttpServer.url,
      tmpdir,
      instructions,
      todoTracker,
      stopScript: repoSettings.stopScript,
      toolState,
      onActivityTimeout: onInnerActivityTimeout,
      onToolUse: (event) => {
        const wasTracked = recordDiffReadFromToolUse({
          state: toolState.diffCoverage,
          toolName: event.toolName,
          input: event.input,
          cwd: process.cwd(),
        });
        if (!wasTracked) return;
        log.debug(`» diff coverage tracked from tool ${event.toolName}`);
      },
    });
    agentPromise.catch(() => {});

    let result: Awaited<typeof agentPromise>;
    if (payload.timeout === TIMEOUT_DISABLED) {
      result = await Promise.race([agentPromise, activityTimeout.promise]);
    } else {
      const usable = resolveTimeoutMs(payload.timeout);
      if (payload.timeout && usable === null) {
        log.warning(`invalid timeout "${payload.timeout}", using 1h`);
      }
      const timeoutMs = usable ?? 3600000;
      const actualTimeout = usable !== null ? payload.timeout : "1h";
      let timeoutId: NodeJS.Timeout | undefined;
      const timeoutPromise = new Promise<never>((_, reject) => {
        timeoutId = setTimeout(() => {
          reject(new Error(`agent run timed out after ${actualTimeout}`));
        }, timeoutMs);
      });
      timeoutPromise.catch(() => {});
      try {
        result = await Promise.race([agentPromise, timeoutPromise, activityTimeout.promise]);
      } finally {
        clearTimeout(timeoutId);
      }
    }

    if (outputSchema && !toolState.output) {
      throw new Error(
        "output_schema was provided but agent did not call set_output — structured output is required"
      );
    }

    if (result.success) {
      core.setOutput("result", result.output ?? "");
      log.success("Task complete.");
      return { success: true, output: result.output };
    } else {
      return { success: false, error: result.error };
    }
  } catch (error) {
    const errorMessage = error instanceof Error ? error.message : "unknown error occurred";
    progressCallbackDisabled = true;
    todoTracker?.cancel();
    killTrackedChildren();
    log.error(errorMessage);
    return { success: false, error: errorMessage };
  } finally {
    activityTimeout?.stop();
    if (safetyNetTimer) clearTimeout(safetyNetTimer);
  }
}